Antireflective hardmask and uses thereof

ABSTRACT

Antireflective hardmask compositions and techniques for the use of antireflective hardmask compositions for processing of semiconductor devices are provided. In one aspect of the invention, an antireflective hardmask layer for lithography is provided. The antireflective hardmask layer comprises a carbosilane polymer backbone comprising at least one chromophore moiety and at least one transparent moiety; and a crosslinking component. In another aspect of the invention, a method for processing a semiconductor device is provided. The method comprises the steps of: providing a material layer on a substrate; forming an antireflective hardmask layer over the material layer. The antireflective hardmask layer comprises a carbosilane polymer backbone comprising at least one chromophore moiety and at least one transparent moiety; and a crosslinking component.

FIELD OF THE INVENTION

The present invention relates to semiconductor devices and, moreparticularly, to antireflective hardmask compositions and techniques foruse of antireflective hardmask compositions for processing semiconductordevices.

BACKGROUND OF THE INVENTION

In the microelectronics industry, as well as in other industriesinvolving construction of microscopic structures, e.g., micromachinesand magnetoresistive heads, there is a desire to further reduce the sizeof structural features. In the microelectronics industry in particular,while the size of microelectronic devices is being reduced, a greateramount of circuitry for a given chip size is being required.

Effective lithographic techniques are essential to reducing the size ofstructural features. Lithography impacts the manufacture of microscopicstructures, not only in terms of directly imaging patterns on thedesired substrate, but also in terms of making masks typically used insuch imaging.

Most lithographic processes use an antireflective coating (ARC) tominimize the reflectivity between an imaging layer, such as aradiation-sensitive resist material layer, and an underlayer to enhanceresolution. However, these ARC materials impart poor etch selectivity tothe imaging layer due to the layers' similar elemental compositions.Therefore, during etching of the ARC after patterning, a lot of theimaging layer is also consumed, which may have been needed foradditional patterning during subsequent etch steps.

In addition, for some lithographic techniques, the radiation-sensitiveresist material employed does not provide resistance to subsequentetching steps sufficient enough to enable effective transfer of thedesired pattern to the layer underlying the radiation-sensitive resistmaterial. In many instances, a hardmask layer is used for example, wherean ultrathin radiation-sensitive resist material is used, where theunderlying layer to be etched is thick, where a substantial etchingdepth is required, where it is desirable to use certain etchants for agiven underlying layer, or any combination of the above. The hardmasklayer serves as an intermediate layer between the patternedradiation-sensitive resist material and the underlying layer to bepatterned. The hardmask layer receives the pattern from the patternedradiation-sensitive resist material layer and transfers the pattern tothe underlying layer. The hardmask layer should be able to withstand theetching processes required to transfer the pattern.

While many materials useful as ARC compositions are known, there is aneed for improved ARC compositions with high etch selectivity to theradiation-sensitive resist material, to the hardmask layer and to theunderlying layer. Further, many of the known ARCs are difficult to applyto the substrate, e.g., applying these ARCs may require the use ofchemical vapor deposition, physical vapor deposition, special solvents,high temperature baking or any combination of the above.

Thus, it would be desirable to be able to perform lithographictechniques with high etch selectivity yet sufficient resistance tomultiple etchings. Such lithographic techniques would enable productionof highly detailed semiconductor devices.

SUMMARY OF THE INVENTION

The present invention provides antireflective hardmask compositions andtechniques for the use of antireflective hardmask compositions forprocessing of semiconductor devices. In one aspect of the invention, anantireflective hardmask layer for lithography is provided. Theantireflective hardmask layer comprises a carbosilane polymer backbonecomprising at least one chromophore moiety and at least one transparentmoiety; and a crosslinking component. The carbosilane polymer maycomprise any combination of an acid generator, an SiO-containing unitand an additional crosslinking component.

In another aspect of the invention, a method for processing asemiconductor device is provided. The method comprises the steps of:providing a material layer on a substrate; forming an antireflectivehardmask layer over the material layer. The antireflective hardmasklayer comprises a carbosilane polymer backbone comprising at least onechromophore moiety and at least one transparent moiety; and acrosslinking component. The method may further comprise the steps of:forming a radiation-sensitive imaging layer over the antireflectivelayer; patternwise exposing the radiation-sensitive imaging layer toradiation thereby creating a pattern of radiation-exposed regions in theimaging layer; selectively removing portions of the radiation-sensitiveimaging layer and the antireflective hardmask layer to expose portionsof the material layer; and etching the exposed portions of the materiallayer, thereby forming a patterned material feature on the substrate.

A more complete understanding of the present invention, as well asfurther features and advantages of the present invention, will beobtained by reference to the following detailed description and drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a flow chart illustrating an exemplary technique forprocessing a semiconductor device according to an embodiment of thepresent invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A lithographic structure comprising an antireflective hardmaskcomposition (hereinafter “the composition”) is disclosed herein. Thecomposition comprises a carbosilane polymer backbone, comprisingcarbosilane units, of the general formula 1:

wherein n≧1, x≧1, and each R group is either a chromophore moiety, atransparent moiety or a crosslinking component.

The carbosilane polymer backbone typically comprises saturated carbon tocarbon bonds, however, unsaturated carbon to carbon bonds may beintroduced into the carbosilane polymer backbone. The introduction ofunsaturated carbon to carbon bonds into the carbosilane polymer backbonewill be described below.

The carbosilane polymer backbone may further comprise SiO-containingunits, wherein SiO comprises any one of, {R₂SiO}, {RSiO_(1.5)} and{SiO₂}, wherein R is an organic group. Exemplary carbosilane polymerbackbones comprising SiO-containing units may be represented as follows:

wherein x≧1, y≧1 and each R group is a chromophore moiety, a transparentmoiety or a crosslinking component. It is to be understood that the term“polymer,” as used herein, refers generally to both carbosilane polymerbackbones comprising carbosilane units and carbosilane polymer backbonescomprising carbosilane units and SiO-containing units.

In an exemplary embodiment wherein the carbosilane polymer backbonecomprises SiO-containing units, the composition has more carbosilaneunits than SiO-containing units to ensure proper hardmask properties ofthe composition (especially when any one of the underlayers comprises anoxide). The SiO-containing units may be chosen from siloxane buildingblocks. The antireflective hardmask layer should have solution andfilm-forming characteristics conducive to layer formation byconventional spin-coating.

The introduction of unsaturated carbon to carbon bonds into thecomposition, e.g., {R₂Si{(CH)₂}_(n)}_(y) or {R₂Si{(C)₂}_(n)}_(z),wherein n≧1 and x=0; y,z≧1 or x,y,z≧1, may be desirable for somelithographic applications, especially those applications employing awavelength of less than or equal to 157 nm. Some exemplary compositionshaving unsaturated carbon to carbon bonds have the followingconfigurations:

The composition may comprise from about 50 weight percent (wt. %) toabout 98 wt. %, on a solids basis, polymer. For example, the compositionmay comprise from about 70 wt. % to about 80 wt. % polymer.

As mentioned above, each R group can be either a chromophore moiety, atransparent moiety, or a crosslinking component. The carbosilane polymerbackbone itself is generally transparent to most wavelengths employed.However, the introduction of fluorine-containing moieties orSiO-containing units, which are substantially transparent to the imagingradiation, may be desirable. In some instances, multiple moieties and/orcrosslinking components may be present on the same carbosilane orSiO-containing unit. For example, a crosslinking component and achromophore moiety may be present on the same carbosilane unit.

The chromophore moiety may comprise any suitable chromophore moietywhich can be grafted onto the carbosilane or SiO-containing units withsuitable radiation absorption characteristics and does not adverselyaffect the performance of either the antireflective hardmaskcomposition, or any overlying radiation-sensitive layers. Suitablechromophore moieties include, but are not limited to, phenyl, chrysenes,pyrenes, fluoranthrenes, anthrones, benzophenones, thioxanthones, andanthracenes. Anthracene derivatives, for example those described inRenner, U.S. Pat. No. 4,371,605 “Photopolymerizable CompositionsContaining N-hydroxyamide and N-hydroxyimide Sulfonates,” the disclosureof which is incorporated by reference herein, may also be used (e.g.,9-Anthracene methanol is a preferred chromophore for 248 nanometer (nm)lithography). The chromophore moiety preferably does not containnitrogen, except for possibly deactivated amino nitrogen such as inphenol thiazine. For 193 nm lithography, non-aromatic compoundscontaining unsaturated carbon bonds, e.g., carbon to carbon doublebonds, are also suitable chromophores. Highly crosslinked carbosilanescan have suitable optical properties at 193 nm without the addition of achromophore. For 157 nm lithography, compounds containing saturatedcarbon to carbon bonds can act as chromophores.

The chromophore moieties may be chemically attached to the carbosilaneor SiO-containing units by acid-catalyzed O-alkylation or C-alkylation,such as by Friedel-Crafts alkylation. Alternatively, the chromophoremoiety may be attached to the carbosilane or SiO-containing units by anesterification mechanism. In an exemplary embodiment, from about onepercent to about 40 percent of the carbosilane and SiO-containing unitscontain chromophore moieties. The site for attachment of the chromophoremoieties on the carbosilane or SiO-containing units can be an aromaticgroup, such as a hydroxybenzyl or hydroxymethylbenzyl group.Alternatively, the chromophore moieties may be attached to thecarbosilane units through reaction with other moieties that are present,such as alcohols. The reaction used to attach the chromophore moietiesto the carbosilane or SiO-containing units preferably comprisesesterification of an alcohol (—OH) group.

The transparent moieties may vary depending on the wavelength orcharacter of the imaging radiation used. In the case of 193 or 157 nmlithography, the transparent moieties used are generally organicmoieties free of unsaturated carbon to carbon bonds. To achievedesirable optical properties for the composition, less than or equal toabout 50 percent of the transparent moieties should contain unsaturatedcarbon to carbon bonds, especially in the case of 193 nm lithography. Inthe case of 157 nm lithography, the transparent moieties may containfluorocarbon substituents to enhance transparency. Further, theformation of polymers comprising a mixture of carbosilane andSiO-containing units may be desirable to achieve optical transparencyfor 193 nm and 157 nm lithography. It may be desirable to balance thenumber of transparent moieties and chromophore moieties to providefavorable combinations of energy absorption and antireflection.

The composition further comprises a crosslinking component. Thecrosslinking component may act, with or without an additionalcrosslinking component, to crosslink carbosilane polymers within thecomposition. The crosslinking reaction may be catalyzed by thegeneration of an acid, by heating, or both, or alternatively, byelectron beam irradiation.

The crosslinking component comprises any suitable crosslinking groupknown in the negative photoresist art which is compatible with othercomponents of the composition. The crosslinking component may act tocrosslink the polymers in the presence of a generated acid. An acidgenerator will be described in detail below.

Suitable crosslinking components include, but are not limited to,glycoluril, alcohols, aromatic alcohols, hydroxybenzyl, phenol,hydroxymethylbenzyl for 248 nm lithography cycloaliphatic alcohols,aliphatic alcohols, cyclohexanoyl, propanol, non-cyclic alcohols,fluorocarbon alcohols, and compositions comprising at least one of theforegoing alcohols. Aromatic alcohols are suitable for 248 nmlithography. Cycloaliphatic and aliphatic alcohols are suitable for 193nm lithography. Further suitable crosslinking components include vinylethers and epoxides.

The crosslinking component may also comprise a silicon hydrogen bond,vinyl or allyl groups or alkoxy substituents attached to silicon.Examples of crosslinkable carbosilanes and examples of R groups, e.g.,of general formula 1, as part of a crosslinking component are shownbelow:

EXAMPLES OF POLYCARBOSILANES

EXAMPLES FOR R=PART OF CROSSLINKING COMPONENT

According to the teachings of the present invention, the composition maycomprise from about one wt. % to about 50 wt. %, on a solids basis,crosslinking component. For example, the composition may comprise fromabout three wt. % to about 25 wt. %, on a solids basis, crosslinkingcomponent.

Generally, the crosslinking component can be attached to the carbosilaneand SiO-containing units by a hydrosilation reaction before, or after,the formation of the polymer. The crosslinking component can also beintroduced to the carbosilane and SiO-containing units by a substitutionreaction of a silicon halogen bond with Grignard or organo lithiumreagents. This substitution reaction may be performed before, or after,formation of the polymer. Examples of hydrosilation reactions I and II,reactions of silicon halogen bond with organometallic reagents III, andvarious polymerization reactions IV, all involving carbosilanes andpolysiloxanes, are shown in the scheme below:

A detailed description of the above examples may be found, for example,in R. D. ARCHER, INORGANIC AND ORGANOMETALLIC POLYMERS, 54, 76 (2001);M. A. BROOK, SILICON IN ORGANIC, ORGANOMETALLIC, AND POLYMER CHEMISTRY,256–367, 400 (2000); M. Birot et al., Comprehensive Chemistry ofPolycarbosilane, Polysilazene, and Polycarbosilazene as Precursors forCeramics, 95 J. CHEM. REV. 1443 (1995); L. V. Interrante et al., Linearand Hyperbranched Polycarbosilanes with Si—CH ₂ —Si Bridging Groups. ASynthetic Platform for the Construction of Novel Functional PolymericMaterials, 12 APPL. ORGANOMETAL. CHEM. 695 (1998); 210H. FREY ET AL.,TOPICS IN CURRENT CHEMISTRY, 101 (2000); E. D. Babich, Silacyclobutanesand Related Compounds (Ring-Opening Polymerization), 10 POLYMERICMATERIALS ENCYCLOPEDIA 7621–35 (1996), the disclosures of which areincorporated by reference herein.

The carbosilane polymer comprising either carbosilane units, or amixture of carbosilane and SiO-containing units, has a weight averagemolecular weight, before reaction with any crosslinking component, ofgreater than or equal to about 500. For example, the carbosilane polymermay have a weight average molecular weight of from about 1,000 to about10,000.

The composition may comprise an additional crosslinking component. Theadditional crosslinking component preferably comprises a compound thatcan be reacted with the carbosilane polymer in a manner which iscatalyzed by a generated acid, and also possibly by heating. Generally,the additional crosslinking component may comprise any additionalcrosslinking agent known in the negative photoresist art which iscompatible with the other components of the composition. Suitableadditional crosslinking agents include, but are not limited to,glycoluril compounds including methylated glycolurils, butylatedglycolurils, tetramethoxymethyl glycoluril,methylpropyltetramethoxymethyl glycoluril,methylphenyltetramethoxymethyl glycoluril,2,6-bis(hydroxymethyl)-p-cresol compounds, etherified amino resinsincluding methylated melamine resins, N-methoxymethyl-melamine,butylated melamine resins, N-butoxymethyl-melamine, bis-epoxies,bis-phenols, bisphenol-A and compositions comprising at least one of theforegoing additional crosslinking agents.

Suitable glycoluril compounds include POWDERLINK™ compounds, a trademarkof Cytec industries. Suitable 2,6-bis(hydroxymethyl)-p-cresol compoundsinclude those described in Masaaki, Japanese Patent ApplicationJP1293339A2 “Photoresist Compositions,” the disclosure of which isincorporated by reference herein. Suitable methylated glycolurils andbutylated glycolurils include those described in Kirchmayr, CanadianPatent 1204547, “Curable Composition Based On an Acid-Curable Resin, andProcess for Curing this Resin,” the disclosure of which is incorporatedby reference herein.

The composition may further comprise an acid generator. The acidgenerator comprises an acid generating group that liberates acid uponthermal treatment (a thermal acid generator). A variety of known thermalacid generators may be used, including, but not limited to,2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyltosylate, other alkyl esters of organic sulfonic acids and compositionscomprising at least one of the foregoing thermal acid generators.Compounds that generate a sulfonic acid upon activation are generallysuitable and include the thermally activated acid generators describedin Sinta et al., U.S. Pat. No. 5,886,102 “Antireflective CoatingCompositions” (hereinafter “Sinta”) and in Pavelchek et al., U.S. Pat.No. 5,939,236 “Antireflective Coating Compositions Comprising PhotoacidGenerators,” (hereinafter “Pavelchek”), the disclosures of which areincorporated by reference herein.

A radiation-sensitive acid generator may be employed as an alternativeto, or in combination with, the thermal acid generator.Radiation-sensitive acid generators generally known in the resist artmay be used, as long as they are compatible with the components of thecomposition. Suitable radiation-sensitive acid generators include thosedescribed in Sinta and Pavelchek.

When a radiation-sensitive acid generator is used, the crosslinkingtemperature may be reduced by the application of radiation to induceacid generation, which in turn catalyzes the crosslinking reaction. Evenif a radiation-sensitive acid generator is used, the composition may bethermally treated to accelerate the crosslinking process. It may beadvantageous to accelerate the crosslinking process, for example, in thecase of production line fabrication.

The composition may comprise from about one wt. % to about 20 wt. %, ona solids basis, acid generator. For example, the composition maycomprise from about one wt. % to about 15 wt. %, on a solids basis, acidgenerator.

In some cases, crosslinking may be achieved by baking in a forming gasatmosphere without either one, or both of, an acid generator or anadditional crosslinker. In the case where an acid generator is not used,crosslinking is accomplished with electron beam radiation instead ofheating.

The composition may be used in combination with any desired resistmaterial to form a lithographic structure. In an exemplary embodiment,the resist material is imageable with shorter wavelength ultravioletradiation, for example, with a wavelength on the order of less than 248nm, or with electron beam radiation. Suitable resist materials aredescribed, for example, in Bucchignano et al., U.S. Pat. No. 6,037,097,“E-beam Application to Mask Making Using New Improved KRS ResistSystem,” the disclosure of which is incorporated by reference herein.

The composition typically comprises a solvent prior to application to adesired substrate. Suitable solvents include solvents conventionallyused with resist materials and which do not have an excessively adverseimpact on the performance of the composition. Exemplary solventsinclude, but are not limited to, propylene glycol monomethyl etheracetate, cyclohexanone and ethyl lactate.

The solvent should be present in the composition in an amount sufficientto achieve a solids content of about five wt. % to about 20 wt. %.Higher solids content formulations will generally yield thicker coatinglayers. The composition of the present invention may further containminor amounts of auxiliary components, e.g., base additives, as areknown in the art.

The compositions provided herein have an adequate shelf-life. Further,the compositions provided herein prevent adverse interactions with theimaging layer, e.g., by acid contamination from the hardmask layer.

The composition can be prepared by combining the carbosilane polymer,crosslinking component and acid generator, as well as any other desiredingredients using conventional methods. The formation of anantireflective hardmask layer using the composition is described below.

The composition is especially useful in conjunction with thelithographic processes used to manufacture semiconductor devices, e.g.,lithographic processes employing 193 nm, 157 nm, x-ray, electron beam orother imaging radiation. Thus, further disclosed herein is a method forprocessing a semiconductor device, as shown in FIG. 1.

Semiconductor lithographic applications generally involve the transferof a pattern to a material layer provided on a semiconductor substrate,as shown in step 102 of FIG. 1. The material layer may be a conductivematerial, a semiconductive material, a magnetic material, an insulativematerial, a metal, a dielectric material or a combination comprising atleast one of the foregoing materials, depending on the stage of themanufacture process and the material desired for the end product.

The composition of the present invention may be formed into anantireflective hardmask layer over the material layer by spin-coating,as shown in step 104 of FIG. 1, followed by baking, to achievecrosslinking and solvent removal. In an exemplary embodiment, baking isconducted at a temperature of less than or equal to about 250 degreescentigrade (° C.). For example, baking may be conducted at a temperatureof from about 150° C. to about 220° C. The duration of baking may varydepending on the thickness of the layers and baking temperature.

In a further exemplary embodiment, baking maybe conducted in a forminggas atmosphere at a temperature of from about 250° C. to about 400° C.In an alternate embodiment, baking is substituted by electron beamradiation.

The thickness of the antireflective hardmask layers formed from thecomposition may vary depending on the desired function. For typicalapplications, the thickness of the antireflective hardmask layer is fromabout 0.03 micrometers (μm) to about five μm.

The antireflective hardmask layers may be used as a dielectric materialin a manner similar to conventional spin-on glass materials. Theantireflective hardmask layers resist lateral etch and may serve as ahardmask layer even at thicknesses generally associated with organicantireflective layers.

The antireflective hardmask layer is preferably applied directly overthe material layer to be patterned. A radiation-sensitive imaging layercan then be formed, either directly or indirectly, over theantireflective hardmask layer, as shown in step 106 of FIG. 1.

The radiation-sensitive imaging layer may be applied using spin-coatingtechniques. The substrate with the material layer, the antireflectivehardmask layer and the radiation-sensitive imaging layer may then beheated, i.e., pre-exposure baked, to remove solvent and improve thecoherence of the radiation-sensitive imaging layer. Theradiation-sensitive imaging layer should be as thin as possible whilestill being substantially uniform and sufficient to withstand subsequentprocessing, such as reactive ion etching, to transfer the lithographicpattern to the underlying material layer. The duration of thepre-exposure bake may be from about ten seconds to about 900 seconds.For example, the duration of the pre-exposure bake may be from about 15seconds to about 60 seconds. The pre-exposure bake temperature may varydepending on the glass transition temperature of the radiation-sensitiveimaging layer.

After solvent removal, the radiation-sensitive imaging layer is thenpatternwise exposed to the desired radiation, for example, ultravioletradiation having a wavelength less than or equal to about 200 nm, i.e.,193 nm ultraviolet radiation, as shown in step 108 of FIG. 1. Whenscanning particle beams, such as an electron beam, are used, patternwiseexposure may be achieved by scanning the particle beam across thesemiconductor device and selectively applying the particle beamaccording to the desired pattern. However, typically, when wavelikeradiation, such as 193 nm ultraviolet radiation, is used, thepatternwise exposure is conducted through a mask which is placed overthe radiation-sensitive imaging layer. The total exposure energy for 193nm ultraviolet radiation may be less than or equal to about 100millijoules per square centimeter (millijoules/cm²). For example, thetotal exposure energy may be less than or equal to about 50millijoules/cm², such as between about 15 millijoules/cm² to about 30millijoules/cm².

After patternwise exposure, the radiation-sensitive imaging layer istypically baked, e.g., post-exposure baked, to further complete theacid-catalyzed reaction and to enhance the contrast of the exposedpattern. The post-exposure bake is conducted at a temperature of fromabout 60° C. to about 175° C. For example, the post-exposure bake may beconducted at a temperature of from about 90° C. to about 160° C. Thepost-exposure bake is preferably conducted for a duration of from about30 seconds to about 300 seconds.

After the post-exposure bake, the radiation-sensitive imaging layer withthe desired pattern is obtained, e.g., developed, by contacting theradiation-sensitive imaging layer with an alkaline solution whichselectively dissolves and removes the areas of the radiation-sensitiveimaging layer which were exposed to the radiation, as shown in step 110of FIG. 1. Suitable alkaline solutions, e.g., developers, includeaqueous solutions of tetramethyl ammonium hydroxide. The resultinglithographic structure is then typically dried to remove any remainingsolvent from the developers.

The desired pattern from the radiation-sensitive imaging layer may thenbe transferred to the exposed portions of the antireflective hardmasklayer by etching with tetrafluoromethoane (CF₄), or other suitableetchant, using known techniques. The portions of the antireflectivehardmask layer may then be removed, as shown in step 110 of FIG. 1.

The exposed underlying material layer to be patterned may then beetched, as shown in step 112 of FIG. 1, using an etchant appropriate tothat material. For example, when the material layer comprises a metalsuch as chromium (Cr) a chlorine/oxygen combination (Cl₂/O₂) may be usedas a dry etchant.

Once the pattern has been transferred to the underlying material layer,any remaining radiation-sensitive imaging layer and antireflectivehardmask layer may be removed using conventional stripping techniques.If the antireflective hardmask layer is being used strictly as ahardmask layer, the composition may be removed using atetrafluoromethane/oxygen (CF₄/O₂) plasma.

The antireflective hardmask and resulting lithographic structure can beused to form patterned features on the substrate, such as metal wiringlines, holes for contacts or vias, insulation sections, includingdamascene trenches or shallow trench isolation trenches for capacitorstructures, and any other like structures that might be used in thedesign of integrated circuit devices. The teachings herein are useful increating patterned material layers of oxides, nitrides, polysilicons orchrome.

Examples of general lithographic processes wherein the composition ofthe present invention may be useful are disclosed in Douglas, U.S. Pat.No. 4,855,017, “Trench Etch Process for a Single-Wafer RIE Dry EtchReactor,” Bronner et al., U.S. Pat. No. 5,362,663, “Method of FormingDouble Well Substrate Plate Trench DRAM Cell Array,” Akiba et al., U.S.Pat. No. 5,429,710, “Dry Etching Method,” Nulty, U.S. Pat. No.5,562,801, “Method of Etching an Oxide Layer,” Golden et al., U.S. Pat.No. 5,618,751, “Method of Making Single-Step Trenches Using Resist FillRecess,” Chan et al., U.S. Pat. No. 5,744,376, “Method of ManufacturingCopper Interconnect With Top Barrier Layer,” Yew et al., U.S. Pat. No.5,801,094, “Dual Damascene Process,” Kornblit, U.S. Pat. No. 5,948,570,“Process for Dry Lithographic Etching,” the disclosures of which areincorporated by reference herein. Other examples of pattern transferprocesses are described in W. MOREAU, SEMICONDUCTOR LITHOGRAPHY,PRINCIPLES, PRACTICES, AND MATERIALS, ch. 12–13 (1988), the disclosureof which is incorporated by reference herein. While exemplarylithographic processes are described and referenced herein, it should beunderstood that the present invention should not limited to anyparticular lithographic technique or device structure.

Further disclosed herein is a patterned lithographic structure. Thepatterned lithographic structure comprises: a substrate; a materiallayer over the substrate; a patterned antireflective hardmask layer overthe material layer, the patterned antireflective hardmask layercomprising the composition; and a patterned radiation-sensitive imaginglayer over the antireflective hardmask layer.

Although illustrative embodiments of the present invention have beendescribed herein, it is to be understood that the invention is notlimited to those precise embodiments, and that various other changes andmodifications may be made by one skilled in the art without departingfrom the scope or spirit of the invention. The following examples areprovided to illustrate the scope and spirit of the present invention.Because these examples are given for illustrative purposes only, theinvention embodied therein should not be limited thereto.

EXAMPLES Example 1

An antireflective hardmask layer was formulated comprisingPolyhydridocarbosilane-co-Allylhydridocarbosilane with ten percent allyl(AHPCS), and Dimethoxypolycarbosilane (DMPCS) obtained from StarfireSystems, Watervliet, N.Y. Polycarbomethylsilane,glycidoxypropyltrimethoxysilane and phenyltrimethoxysilane were obtainedfrom Aldrich Chemical Company, Inc.

Example 2

Formulation A, Film Formation:

The polymer AHPCS was dissolved in 2-heptanone solvent at aconcentration of about ten wt. % to about 20 wt. %, on a solids basis,relative to the solvent. A film with a thickness of about 200 nm toabout 400 nm was generated by spin coating Formulation A onto a 200millimeter (mm) silicon wafer at 3000 revolutions per minute (rpm) for60 seconds, followed by a hot plate bake at 200° C. for five minutesunder an inert nitrogen flow, and a furnace cure at 400° C. for one hourunder an inert nitrogen flow. Rutherford backscattering spectrometry(RBS) analysis of the carbosilane polymer film cured at 200° C. showedthe following elemental composition: silicon 23.9±2 atomic percent;carbon 25.9±3 atomic percent; hydrogen 44.9±2 atomic percent; oxygen5.3±3 atomic percent. RBS analysis of the polycarbosilane polymer filmcured at 400° C. showed the following elemental composition: silicon22.5±2 atomic percent; carbon 29.7±3 atomic percent; 40.0±2 atomicpercent; oxygen 7.8±3 atomic percent.

Example 3

Formulation B, Film Formation:

The polymer polycarbomethylsilane was dissolved in 2-heptanone solventat a concentration of about ten wt. % to about 20 wt. %, on a solidsbasis, relative to the solvent. A film with a thickness of about 200 nmto about 400 nm was generated by spin coating Formulation B onto a 200mm silicon wafer at 3000 rpm for 60 seconds, followed by a hot platebake at 200° C. for five minutes under an inert nitrogen flow. The filmwas then electron beam cured by exposure using a ElectronCure™—200M toolfrom the AlliedSignal ElectronVision Group. The exposure was done withtwo milliamps (mA) at 25 kilovolts (kV) for approximately 20 minutes.The dose is exactly at 2000 microcoulombs per square centimeter (μC/cm²)for each wafer. The maximum dose on this tool is 250 (microcoulombs) μCeach time. It was exposed eight times with 250 μC each.

Example 4

Formulation C, film formation:

The polymer DMPCS was dissolved in PGMEA solvent at a concentration of20 wt. % relative to the solvent. The thermal acid generator,nitrobenzylbutyltosylate, was added at a concentration of five wt. %relative to the polymer. A film with a thickness of 200 nm was generatedby spin coating the formulation onto a 200 mm silicon wafer at 3000 rpmfor 60 seconds, followed by a hot plate bake at 200° C. for two minutes.

Example 5

Formulation D:

The precursors dimethoxypolycarbosilane (DMPCS),glycidoxypropyltrimethoxysilane and phenyltrimethoxysilane were mixed ina molar ratio of 0.45 to 0.45 to 0.1, respectively. A total of one gram(g) of this mixture was dissolved in four g of Dowanol PM (a product ofAldrich Chemical Company, Inc.) and one g of one normal (n) hydrochloricacid. This solution was stirred for one hour and filtered. A film with athickness of 300 nm was generated by spin coating this formulation ontoa 200 millimeters (mm) silicon wafer at 3000 rpm for 60 seconds,followed by a hot plate bake at 200° C. for two minutes. RBS analysis ofthe silsesquioxane/carbosilane copolymer film showed the followingelemental composition: silicon 11.7±2 atomic percent; oxygen 19.8+2atomic percent; carbon 27.7±2 atomic percent; hydrogen 40.1±2 atomicpercent; chlorine 0.7±0.2 atomic percent.

Example 6

Optical Properties:

The optical constants (index of refraction (n) and extinctioncoefficient (k) at 193 nm) are measured using an n&k Analyzermanufactured by n&k Technology, Inc.

The optical properties of the films for 193 nm radiation were asfollows:

Film Polymer n k Formulation A 1.922 0.414 Formulation B 1.726 0.39Formulation C 1.67 0.007 Formulation D 1.909 0.247

The optical properties of the films for 157 nm radiation were asfollows:

Film Polymer n k Formulation C 1.859 0.210

Example 7

193 nm Lithography and Etching the antireflective hardmask layer:

The antireflective hardmask layer, described in Example 1 and Example 4,was used for lithography. A layer of acrylic-based photoresist, aproduct of Sumitomo, JSR, was spin-coated over the cured antireflectivehardmask layer to a thickness of about 250 nm. The radiation-sensitiveimaging layer was baked at 130° C. for 60 seconds. Theradiation-sensitive imaging layer was then imaged using a 0.6 NA 193 nmNikon Stepper with conventional and annular illumination using APSMreticle. After patternwise exposure, the radiation-sensitive imaginglayer was baked at 130° C. for 60 seconds. The image was then developedusing a commercial developer (0.26M TMAH). The resulting pattern showed113.75 nm and 122.5 nm lines and space patterns.

The pattern was then transferred into the antireflective hardmask layerby a 20 second fluorocarbon-based etch using a TEL DRM tool. The etchselectivity between the radiation-sensitive imaging layer and thehardmask layer exceeded three to one.

The etch selectivity between the films present between theantireflective hardmask layer and an oxide containing material layer wasdetermined on the polymer films from Example 1 to be five to one andpolymer films from Example 4 to be three to one, using afluorocarbon-based oxide etch performed on a TEL DRM tool. The combinedetch selectivities will give an overall etch selectivity of the patterntransfer from oxide to organic resist material greater than six to one.

Example 8

All of the following reactions were carried out under an inertatmosphere using standard Schlenk techniques. Anhydrous toluene, allylglycidyl ether and polycarbomethylsilane (MeH-PCS) were purchased fromAldrich Chemical Company, Inc., and used as received. Karstedt'sCatalyst was purchased from Gelest, Tullytown, Pa. whiledimethyldisilacyclobutane (MeH-DSCB) was purchased from StarfireSystems, Watervliet, N.Y. Tetramethyldisilacyclobutane (Me₂-DSCB) wassynthesized according to procedures obtainable commercially from AldrichChemical Company, Inc. The optical constants (index of refraction (n)and extinction coefficient (k) at 193 nm) are measured using an n&kAnalyzer manufactured by n&k Technology, Inc.

Hydrosilylation of MeH-DSCB with allyl glycidyl ether (AGE)

MeH-DSCB (2.95 g, 25.4 millimole (mmol)) and AGE (7.25 g, 623.6 mmol)was placed in a 50 milliliter (mL) Schlenk flask and degassed via twofreeze/thaw cycles. Anhydrous toluene (15 mL) was added followed by theaddition of ten microliters (μL) of Karstedt's Catalyst, and thereaction was stirred at room temperature for 18 hours. A couple ofspatula tips of silica gel were added and the reaction continuedstirring at room temperature for eight additional hours. Filtration,followed by the removal of volatile components under vacuum, affordedMeGP-DSCB (Methyl-Glycidoxypropyldisilacyclobutane) (67 percent isolatedyield). ¹H NMR (400 megahertz (MHz), CDCl₃): 0.05 (m, 2H,Si(Me)(CH₂R)CH₂Si), 0.28 (m, 3H, Si(Me)(CH₂R)CH₂Si), 0.73 (m, 2H,Si(Me)(CH₂CH₂R)CH₂Si), 1.70 (m, 2H, Si(Me)(CH₂CH₂R)CH₂Si), 2.65 (m, 1H,GP), 2.83 (m, 1H, PGE), 3.19 (m, 1H, GP), 3.45 (br, 1H, GP), 3.78 (br,1H, PGE).

Synthesis of Methyl-Glycidoxypropyl-Polycarbosilane (MeGP-PCS):Ring-Opening Polymerization of MeGP-DSCB.

MeGP-DSCB (1.00 g, 2.91 mmol) was placed in a Schlenk tube and degassedvia two freeze/thaw cycles. Anhydrous toluene (15 mL) was added followedby the addition of five μL of Karstedt's Catalyst. Following a slightexotherm, the reaction was heated at 75° C. overnight. Precipitation inMeOH at −78° C. and removal of residual solvents afforded MeGP-PCS (50percent isolated yield). ¹H NMR (400 MHz, CDCl₃): −0.23 (m,Si(Me)(R)CH₂SiMe(R′)), 0.11 (m, Si(Me)(R)CH₂SiMe(R′)), 0.52(m,Si(Me)(CH₂CH₂R)CH₂Si), 1.62 (m, Si(Me)(CH₂CH₂R)CH₂Si), 2.65 (m, GP),2.83 (m, GP), 3.19 (m, PGE), 3.44 (br, GP), 3.78 (br, GP). Mn=3483,PDI=2.91.

Synthesis of (MeGP-co-Me₂)PCS: Copolymerization of Me₂-DSCB andMeGP-DSCB

MeGP-DSCB (0.5 g, 1.45 mmol) and Me₂-DSCB (0.21 g, 1.45 mmol) wereplaced in a Schlenk tube and degassed via two freeze/thaw cycles.Anhydrous toluene (15 mL) was added followed by the addition of five μLof Karstedt's Catalyst. Following a slight exotherm, the reaction washeated at 75° C. overnight. Precipitation in MeOH at −78° C. and removalof residual solvents afforded (MeGP-co-Me₂)PCS as a viscous liquid (33percent isolated yield). ¹H NMR (400 MHz, CDCl₃): −0.23 (m,Si(Me)(R)CH₂SiMe(R′)), 0.16 (m, Si(Me)(R)CH₂SiMe(R′)), 0.55 (m,Si(Me)(CH₂CH₂R)CH₂Si), 1.65 (m, Si(Me)(CH₂CH₂R)CH₂Si), 2.65 (m, GP),2.83 (m, GP), 3.19 (m, GP), 3.44 (br, GP), 3.77 (br, GP). Opticalproperties (193 nm): n=1.681, k=0.032.

Synthesis of Branched MeGP-PCS: Hydrosilylation of MeH-PCS

MeHPCS (molecular weight (mw)=800, 2.00 g) and AGE (8.80 g, 77.2 mmol)were combined in a flask and degassed via two freeze/thaw cycles.Anhydrous toluene (15 mL) was added followed by the addition of H₂PtCl₆(ca. five μL of a 0.1 molar (M) solution in iPrOH). The reaction washeated at 95° C. overnight. Precipitation into cold MeOH (−78° C.)followed by removal of the supernatant solvent affords the desiredMeGP-PCS (68 percent, isolated yield, 18 percent grafting). ¹H NMR (400MHz, CDCl₃): 0.043–0.146 (br, Si(Me)(CH₂R)CH₂Si), 1.56 (br, 2H,Si(Me)(CH₂CH₂R)CH₂Si), 2.58 (br, 1H, GP), 2.77 (br, 1H, GP), 3.12 (br,1H, GP), 3.39 (br, 1H, GP), 3.69 (br, 1H, GP). GPC: Mn=1900, PDI=1.8.

Formulation for Spin-coating

MeGPPCS was dissolved in PGMEA to afford a ten wt. %, on a solids basis,relative to the solvent. t-Butylphenyldiphenylsulfoniumperfluorobutanesulfanate (TAG) was added such that the composition ofTAG relative to polymer was 2.5 wt. %. Surfactant (FC430) was added toconstitute 1,500 parts per million (ppm) relative to the total mass. Afilm with a thickness of 215 nm was spin coated on 25 mm wafer at 3,000rpm for 40 seconds, and baked at 110° C. for 60 seconds. Opticalproperties (193 nm): n=1.674, k=0.025. Cross-linking was accomplished bybaking the wafer at 220° C. for 60 seconds resulting in a film that wasinsoluble in any solvents.

(MeGP-co-Me2)PCS copolymer was dissolved in PGMEA to afford a ten wt. %,on a solids basis, relative to the solvent. TAG(tbutylphenyldiphenylsulfonium perfluorobutanesulfanate) was added suchthat the composition of TAG relative to polymer was 2.5 wt. %.Surfactant (FC430) was added to constitute 1,500 ppm relative to thetotal mass. A 300 nm thick film was spin coated on a 25 mm wafer at3,000 rpm for 40 seconds and baked at 110° C. for an additional 60seconds. Optical properties (193 nm): n=1.681, k=0.032. Cross-linkingwas effected by heating at 220° C. for 60 seconds.

Branched MeGPPCS was dissolved in PGMEA to afford a ten wt. % on asolids basis, relative to the solvent. TAG(tbutylphenyldiphenylsulfonium perfluorobutanesulfanate) was added suchthat the composition of TAG relative to polymer was 2.5 wt. %.Surfactant (FC430) was added to constitute 1,500 ppm relative to thetotal mass. A film with a thickness of 118 nm was spin coated on a 25 mmwafer at 3,000 rpm for 40 seconds, and baked at 110° C. for 60 seconds.Cross-linking was effected by heating at 220° C. for 60 seconds. Opticalproperties (193 nm): n=1.750, k=0.084.

1. An antireflective hardmask layer for lithography, comprising: acarbosilane polymer backbone comprising at least one chromophore moietyand at least one transparent moiety; and a crosslinking component,wherein the crosslinking component comprises a crosslinking groupselected from the group consisting of glycoluril, alcohols, aromaticalcohols, hydroxybenzyl, phenol, hydroxymethylbenzyl, cycloaliphaticalcohols, aliphatic alcohols, cyclohexanoyl, propanol, non-cyclicalcohols, fluorocarbon alcohols, vinyl ethers, epoxides and compositionscomprising at least one of the foregoing crosslinking groups.
 2. Theantireflective hardmask layer of claim 1, wherein the carbosilanepolymer backbone comprises SiO-containing units.
 3. The antireflectivehardmask layer of claim 2, wherein the carbosilane polymer backbonecomprises more carbosilane than SiO-containing units.
 4. Theantireflective hardmask layer of claim 1, further comprising anadditional crosslinking component.
 5. The antireflective hardmask layerof claim 4, wherein the additional crosslinking component comprises anadditional crosslinking group selected from the group consisting ofglycoluril, methylated glycoluril, butylated glycoluril,tetramethoxymethyl glycoluril, methylpropyl tetramethoxymethylglycoluril, methylphenyltetramethoxymethyl clycoluril,2,6-bis(hydroxylmethyl)-p-cresol, etherified amino resins, methylatedmelamine resins, N-methoxymethyl-melamine, butylated melamine resins,N-butoxymethyl-melamine, bis-epoxies, bis-phenols, bisphenol-A andcompositions comprising at least one of the foregoing additionalcrosslinking groups.
 6. The antireflective hardmask layer of claim 1,wherein the carbosilane polymer backbone comprises unsaturated carbon tocarbon bonds.
 7. The antireflective hardmask layer of claim 1, whereinthe carbosilane polymer backbone comprises saturated carbon to carbonbonds.
 8. The antireflective hardmask layer of claim 1, comprising fromabout 50 wt. % to about 98 wt. %, on a solids basis, carbosilane polymerbackbone.
 9. The antireflective hardmask layer of claim 1, comprisingfrom about 70 wt. % to about 80 wt. %, on a solids basis, carbosilanepolymer backbone.
 10. The antireflective hardmask layer of claim 1,wherein each chromophore moiety comprises a moiety selected from thegroup consisting of phenyl, chrysenes, pyrenes, fluoranthrenes,anthrones, benzophenones, thioxanthones, anthracenes, anthracenederivatives, 9-anthracene methanol, phenol thiazine, non-aromaticcompounds containing unsaturated carbon to carbon double bonds,compounds containing saturated carbon to carbon bonds and compositionscomprising at least one of the foregoing moieties.
 11. Theantireflective hardmask layer of claim 1, wherein the carbosilanepolymer backbone is transparent to one or more wavelengths of radiation.12. The antireflective hardmask layer of claim 1, wherein eachtransparent moiety is transparent to 157 nanometer radiation.
 13. Theantireflective hardmask layer of claim 1, wherein a given number of theat least one transparent moiety comprise an organic moiety.
 14. Theantireflective hardmask layer of claim 13, wherein a given number of theat least one transparent moiety comprise an a fluorocarbon substituent.15. The antireflective hardmask layer of claim 1, comprising from aboutone wt. % to about 50 wt. %, on a solids basis, crosslinking component.16. The antireflective hardmask layer of claim 1, comprising from aboutthree wt. % to about 25 wt. %, on a solids basis, crosslinkingcomponent.
 17. The antireflective hardmask layer of claim 1, furthercomprising an acid generator.
 18. The antireflective hardmask layer ofclaim 17, wherein the acid generator comprises an acid generating groupselected from the group consisting of2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyltosylate, alkyl esters of organic sulfonic acids and compositionscomprising at least one of the foregoing acid generating groups.
 19. Theantireflective hardmask layer of claim 17, wherein the acid generatorcomprises a thermal acid generator.
 20. The antireflective hardmasklayer of claim 17, comprising from about one wt. % to about 20 wt. %, ona solids basis, acid generator.
 21. The antireflective hardmask layer ofclaim 17, comprising from about one wt. % to about 15 wt. %, on a solidsbasis, acid generator.
 22. A lithographic structure, comprising: asubstrate; a material layer over the substrate; an antireflectivehardmask layer over the material layer, the antireflective hardmasklayer comprising: a carbonsilane polymer backbone comprising at leastone chromophore moiety and at least one transparent moiety; acrosslinking component, wherein the crosslinking component comprises acrosslinking group selected from the group consisting of glycoluril,alcohols, aromatic alcohols, hydroxybenzyl, phenol, hydroxymethylbenzyl,cycloaliphatic alcohols, aliphatic alcohols, cyclohexanoyl, propanol,non-cyclic alcohols, fluorocarbon alcohols, vinyl ethers, epoxides andcompositions comprising at least one of the foregoing crosslinkinggroups; and a radiation-sensitive imaging layer over the antireflectivehardmask layer.